125+ Hours. Time for a top end job

[AZRickD]

In the middle of Arizona's race season and multiple Holiday's off, I decided it was time freshen up this 2011 EC250R. A Vertex piston from MotoCity.

This is my 3rd effort on a GG top-end (three on my 2005 EC250 back in 2011).

Any advice is appreciated.

 

[AZRickD]

Sticking with the A-cylinder.

The motor came out of the factory with a .5mm base gasket. I think I'll go with the .3mm.

With my RB head mod, the squish band measures at about 1.35mm as it sat with the .5 base gasket. I originally had it set at about 1.05mm with a .3mm.

The power valve looks too good for me to mess with it. Leaving it as is.

I am hoping that I don't install the PV linkage backward, somehow. Is that possible?

 

[AZRickD]

Piston pics.

 

[AZRickD]

Doing heat cycles.

 

[Jakobi]

What jetting had you been running?

 

[liv2day]

I am hoping that I don't install the PV linkage backward, somehow. Is that possible?

Hey Rick -

It sounds like you already have everything together, but for future reference, this was a huge help to me when I did the top end on my 200 for the very first time: http://www.gasgasrider.org/pv_disassembly_mattr.pdf

These two YT videos were instrumental as well; show the PV assembly on a GG300.

https://www.youtube.com/watch?v=hmz9cij6MVY

https://www.youtube.com/watch?v=FQJs2qM3rT8

Hope she runs like a beast and that new piston gives her lots of pull

 

[AZRickD]

Liv2Day, Thanks for the links.

Jakobi, I'm running a Lectron. I tend to run things fairly rich. Most riding in Phoenix is between 1K and 3K feet. I don't change anything when I go to Flagstaff (7K to 9K).

Bottom of the piston is barely discolored. Two small amber areas.

Time to do one more heat cycle this morning then I'll let her rip.

 

[AZRickD]

How's the heat and mixture ?

 

[AZRickD]

Piston top --

 

[GGRider01]

At least you can read the writing on the top of yours. I got my bike with the original piston in it.. 15 years after it came to the US. There was at least a 1/16th of an inch of carbon caked on the top. It had no carbon below the rings, interestingly. Washed perfectly clean and shiny like a mirror.. It was definitely overdue.

 

[AZRickD]

That amount of blow by after just 125 hours is puzzling.

I consider myself a lugger on trail riding and even during some races. But a lot of our races have miles if fast sand wash and two combine tail with MX track.

 

[Jakobi]

Ahh the lectron! Little hot spot under looks about right. I'm yet to have a piston come out without a little glazing, but some have been run leaner than others for sure.

What exactly do you find interesting re the blow by? My latest piston at 65hrs shows much less, but the rings were at max spec and comp was notably down. Have you measured your end gaps?

 

[AZRickD]

I usually (always) have much less blow-by. Maybe a few millimeters below the rings. My normal routine is to swap out piston and/or the rings at under 100 hours just because I'm paranoid and like to see how things are going. That, and there is always a boost in power. This maintenence period is an outlier for me.

I guess the difference between say 90 hours an 130 hours is more than I anticipated.

The rings were just a titch out of spec.